Lack of sleep, and the health problems that are caused by lack of sleep, are significant problems for public health and safety. One key component of effective research on sleep health is the ability to objectively track and measure degradation in performance due to sleep deprivation. This application is in response to NIH PA-05-046, "Research in Sleep and Sleep Disorders", which solicits applications to conduct research on novel methods for measurement of sleep and sleepiness. In preliminary work with a small set of subjects, we have found that subtle articulatory patterns automatically extractable from the acoustic spectrum can differentiate the speech articulation of rested individuals from that of sleep-deprived individuals. The immediate aim of this exploratory project is to test the hypothesis that speech articulation changes under sleep deprivation conditions in a reliable way. At present time, there is sparse information regarding the interaction of sleep and language or speech. In particular, there has been little scientific investigation of language and speech production. Thus, the first specific aim of this project is to test the validity and consistency of our findings over a larger and more varied corpus of data. We have recently arranged to acquire three large sets of speech recording data collected at intervals in the course of carefully conducted sleep deprivation studies. We will analyze these data for evidence of changes in speech articulation across "fresh" and "sleep-deprived" conditions. A second specific aim is to develop our analysis tool as a potential method for objective measurement of performance degradation under sleep deprivation. A third focus of the project will be to characterize the difference in patterns associated with "fresh" vs. "sleep deprived" speech. This project will lead to a research program that will investigate in detail the impact of biologically and socially driven speaking conditions on motor control for speech production. Practical human health implications of this research may include better monitoring of performance effectiveness and better understanding of behavioral responses to sleep deprivation. [unreadable] [unreadable] [unreadable]